Data Scientist

New York City
About Citizen

Citizen’s mission is to protect the world. We began by opening the NYC and San Francisco 911 system to local Citizen app users, creating access to real-time crime and safety information. By increasing situational awareness and transparency, we hope communities will become safer than ever before.

Since our launch, 3% of New Yorkers use our app every month, and that growth is accelerating. We launched San Francisco last fall, and over 1% has already joined the Citizen safety network. We send over 4 million nearby crime notifications each month, alerting our users to emergencies and dangerous situations near them. Citizen broke both recent NYC terror incidents to people nearby, keeping thousands in the vicinity safer and informed in real-time. Citizen has been featured on local NYC news over 100 times in the past 3 months. 

We’re looking for passionate, mission-driven individuals to help take the Citizen app to the next level as we scale up new cities and expand globally.

Citizen is backed by Sequoia Capital and Founder’s Fund. 

Our Challenges

    • Scaling: We have one of the fastest growing organic user bases in NYC, and right now we’re geo-restricted to New York City and San Francisco. Soon we will launch nationwide and we need to support that scale. A Citizen international launch will follow.
    • Bursting: Without warning, a major incident occurs and multiple users begin live-streaming video into the app. We notify the entire user base, causing a massive burst of simultaneously connected clients. The core systems we build need to efficiently support traffic that can grow to hundreds of thousands of concurrent users today, and millions in the future.
    • Analytics: We want to alert users to incidents that matter to them, in a way that scales across different geographic densities and demographics.
    • Mobile video streaming: Our app will ingest high-quality video at low-latency, transcode, and redistribute the video to external media outlets seamlessly.
    • Extracting signal from noise: During major breaking news events, tensions are high and a lack of information persists. We build tools to raise facts and suppress noise.
    • FM radio: We use software-defined radios to consume all radio dispatch in NYC, SF and eventually every major city, whether analog, digital, or trunked.

Our Stack - languages and technologies we use and teach

    • Mobile: Swift (iOS), Java (Android)
    • Web: React.js
    • Server: Go, Node (for isolated systems)
    • Systems: MySQL, Redis, Kafka, Firebase (for isolated systems)
    • Infrastructure: Kubernetes on GCP

Role Description

    • Our core challenges come from intersecting our growing internal datasets on user behavior and real time crime, fire, and medical incidents with large, messy external datasets from governmental and private sources.
    • Work with a wide array of real-world data sources, with an inclination towards experimentation, to find new and better data sources that allow us to further customize our users’ notifications and overall experience.
    • Work with the executive team in support of our mission by helping inform Mayors, Governors, Chiefs of Police, and other public figures with data-led analysis of the impact of Citizen on crime
    • Lead projects that derive value from our unique, rich, and rapidly growing data.
    • Distilling questions, wrangling data, and driving decisions with data analytics. 
    • Work with Engineering to evangelize data best practices and implement data analytics solutions.
    • Working with Product to inform prioritization of roadmap through data analytics


    • Bachelor’s Degree in Computer Science, Math, Statistics, or related field.
    • 5+ years of experience in data science or analytics.
    • Proficiency in programming/scripting and experience with statistical packages like R, Python/Pandas, etc.
    • Strong knowledge of relational databases and ability to write SQL code at an expert level.
    • Aptitude with numbers, intellectual curiosity about metrics and measuring impact.
    • Enjoys teaching and collaborating with others.